# C[omp]ute

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Always interested in offers/projects/new ideas. Eclectic experience in fields like: numerical computing; Python web; Java enterprise; functional languages; GPGPU; SQL databases; etc. Based in Santiago, Chile; telecommute worldwide. CV; email.

© 2006-2015 Andrew Cooke (site) / post authors (content).

## Pro-Django Review

From: andrew cooke <andrew@...>

Date: Sun, 8 May 2011 05:27:18 -0300

I just found this on my heard drive; it was written quite a while ago, but
never posted.

Andrew

This is a curious book.  When I heard of it, about 6 months ago, I found mixed
online reviews.

All the references I need are online, carefully indexed by Google.  I only buy
books that give more than that; books that require, and reward, a complete

But I continued to stumble over references.  One day, chatting online with a
less-than-impressed reader, I offered to buy their copy for \$10, curious to
understand the range of reactions.  Deal.

Others may also be curious, so here is my explanation of the mixed reviews.
As you might expect, it is both better and worse than I expected: it's smart,
but a dumb kind of smart.

I can illustrate that with the section that introduces signals.  These are
events raised by Django that you subscribe to, with names like pre_save and
post_save.  Those names might remind you, as they did me, of the way CLOS (the
Common Lisp Object System) lets you extend methods before or after they are
called.  And then, if you gaze out of the window, as I did, you might start to
think that signals are just another way of decorating methods.

Pro-Django says nothing of this, but it does give a lot of details about
signals.  If you like details, that's great.  But I'm too old for details: I
need generalisations.

Generalisations are good, even if you're not senile.  They're good because
they lead places you already know.  Places like: if signals are like method
decorations, what happens when the method raise an exception?  Hmmm.

Now Pro-Django explains how exceptions interact with signals, in grey box, a
page later, because it has all the details.  That's the problem: it's just
another bloody detail.  There's no arch to bring it all together.

But before you nod sagely in agreement, could you have done any better?  I
don't think I could.  Writing books is hard.  This is a meaty book, dense with
facts hard-earned from hours of reading code.  How do you tie all that
together?  One way is with examples.  He has examples.  Good, meaty examples.
Another way is with careful hierarchical structure.  Also present (although
the page design doesn't show them too well).  He's trying.

It's not great.  I don't know how to do great; the author doesn't either.  But
I still found it worth reading, slowly.

To do the book more justice, I can explain why the first chapter - the one you

The first chapter is a summary of standard, but slightly obscure, Python
techniques.  Things a newbie programmer doesn't know, but anyone that has
lived with Python for years does: decorators, metaclasses, etc.

I read that, and was bored.  But imagine that you only know Python through
Django.  From that perspective, the chapter is critical.  And with that
insight, I think you can get a better understanding of rest of the book: it
does for Django what that first chapter does for Python.

The first chapter is a terrible example for anyone that knows Python in depth,
because it's old news.  But I don't know Django as well as I do Python, so the
rest of the book is much better.

It's still not a great read.  You need to stop, think, and build the
generalisations yourself.  Which makes it slow, hard work.  But, for me, it
was worth the effort.

### Pro Django Review

From: Marty Alchin <marty@...>

Date: Sun, 08 May 2011 06:15:33 -0700

Andrew,

I wanted to thank you for your thoughtful review of Pro Django. I'm glad
you found it worth the read, but I'm particularly pleased that you took
the time to explain the issues you had with it. So many reviews have
hinted at some of the problems you mentioned, but never bothered to
actually describe them, so I was left scratching my head a bit as to
what I could've done better. Your description definitely helped me
understand it a lot better.

What you observed was actually a symptom of an intentional choice to
avoid generalizations and TL;DR descriptions where I could, figuring
solely for the meat of the details you mentioned. Given how many other
reviews have expressed similar frustrations, it looks like I need to
work on a better mix. If I end up writing a second edition, I'll
definitely take this into account, and I just wanted to thank you for

-Marty

### Re: Pro Django Review

From: andrew cooke <andrew@...>

Date: Mon, 9 May 2011 09:42:16 -0400

I'm glad I could help.  Reviewing a book is always a bit worrying because I'm
arbitrarily criticising a huge amount of work, and it seems even more unfair
when I haven't written book myself.  So I'm sorry if any of it was unjust.
I've just read the review again (sorry about all the typos too!) and I think
one point you don't mention (perhaps you had no choice in the matter) was the
example chapter - any other chapter than the first would have been a much
better example of what the book contained.

Anyway, good luck and thanks for writing that book!

Andrew

PS Your email was automatically added to my site.  I assume that's what you
expected, but email me if not.  (It's the first time it's ever worked
automatically! - I don't get many comments... :o)